Every day there is increased use and installation of renewable energy. The highest percentage of installed renewable energy goes to hydro power, wind power and then comes solar power. Geothermal energy as a source has advantage over the other renewables and that is to produce electricity regardless whether it is day or night, regardless of

Every day there is increased use and installation of renewable energy. The highest percentage of installed renewable energy goes to hydro power, wind power and then comes solar power. Geothermal energy as a source has advantage over the other renewables and that is to produce electricity regardless whether it is day or night, regardless of weather and climate conditions.

There are two main types of geothermal sources thatÂ produce electricity. Those are hydrothermal and petrothermal. Hydrothermal sourcesÂ comes from natural geothermal fluid which are located underground. The fluid isÂ used as thermal source and it is taken out using boreholes. Hydrothermal sourcesÂ are located only in certain places and therefore they are quite rare. On theÂ other hand petrothermal sources are widespread, but rarely exploited. These sourcesÂ mainly consist of â€œheat in placeâ€ in deep rock formations underground.

Currently there is 12 GWe from geothermal energyÂ installed in the world in 24 countries. 99% of those 12 GWe is produced fromÂ hydrothermal sources. Production of electricity from geothermal energy startedÂ in 1904 in Landarello, Italy. The largest geothermal power plant is located inÂ New Zealand with the power of 140 MWe and power is derived from 6 geothermalÂ wells.

According to World Energy Assessment (WEA) potential ofÂ geothermal energy is huge. You can see data for potential in table 1.

TableÂ 1. Potential of renewable energy according to WEA

Energy source

Potential (EJ/yr.)

Geothermal

5000

Solar

1575

Wind

640

Biomass

276

Hydro

50

Total

7541

The growth of installed geothermal power plants is practicallyÂ linear.

According to the Geothermal Energy Association growth from 2000 to 2013Â is small. In recent years there was a rise in installedÂ capacities of solar and wind energy. It resulted that today there is 319 GW ofÂ installed wind power and 139 GW of installed solar power plants in the world. WindÂ cannot blow constantly and wind power plants cannot work for 24 hours. The sunÂ only shines during a day and solar power plants produce electricity only during
day. Geothermal power plant can produce electricity continuously (except inÂ maintenance time). The next table shows the installed capacity of renewableÂ energy and their annual production.

From the review we can conclude that there is potentialÂ for geothermal energy. The only thing is to use that potential in right way. ThisÂ type of renewable energy produces electricity 24 hours a day, it does notÂ require wind or sun. It remains to be seen what is going to happen to investmentsÂ in this sector and whether capacities will increase in coming years.